In 1987 San Diego County residents approved the 20-year TransNet Program, a one-half cent sales tax to fund a variety of transportation projects throughout San Diego County. This program, which was scheduled to expire in 2008, is one of the largest transportation improvement programs in California.

In November 2004, voters approved an extension ordinance and expenditure plan (Proposition A) that extends the TransNet program to 2048. This extension is expected to generate approximately $14 billion to be distributed among highway, transit, and local road projects to reduce traffic congestion in San Diego County. The San Diego Association of Governments (SANDAG) administers the funds generated by TransNet.

Proposition A mandated the formation of an Independent Taxpayer Oversight Committee (ITOC) for TransNet. This committee provides oversight for the expenditure of TransNet funds and ensure that voter mandates are carried out. The ITOC also makes recommendations to improve the program’s financial integrity and performance.

Partnering with Caltrans, MTS, and NCTD, SANDAG has shifted into high gear to accelerate a variety of high-priority, TransNet-funded transportation improvements throughout the region. These major construction and infrastructure projects, called Early Action Projects, include I-5; I-15; I-805; State Routes 52 and 76; the Mid-Coast transit extension from Old Town to the UCSD/University Towne Centre area; I-15 Bus Rapid Transit (BRT) from Escondido to downtown San Diego via Mid-City; the South Bay BRT from Otay Ranch to downtown San Diego via I-805; and the Mid-Coast Transit Super Loop in the University City area. Several of the major interstate projects, such as I-15, also include the incorporation of managed lane systems.